Spontaneous fission
Spontaneous fission (SF) is a form of radioactive decay in which a heavy atomic nucleus splits into two or more lighter nuclei. In comparison to induced fission, there is no inciting particle to trigger the decay, it is a purely probabilistic process.
Nuclear physics |
---|
|
Spontaneous fission is a dominant decay mode for superheavy elements, with nuclear stability generally falling as nuclear mass increases. It thus forms a practical limit to heavy element nucleon number. Heavier nuclides may be created instantaneously by physical processes, both natural (via the r-process) and artificial, though rapidly decay to more stable nuclides. As such, apart from minor decay branches in primordial radionuclides, spontaneous fission is not observed in nature.
Observed fission half-lives range from 4.1 microseconds (250
102No
) to greater than the current age of the universe (232
90Th
).: 16